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ECODRIVE03-FL*-04VRS
DOK-ECODR3-FL*-04VRS**-FK01-EN-P
Communication Between Master and Slave
A general description of the communication relationships is illustrated in
the following graphic. The following two services are shown from the
perspective of the master:
•
Read Request
•
Write Request
Master
Read
Request
Fig. 11-17: Master Reads Datum
Master
Write
Request
Fig. 11-18: Master Writes Read or Write Request
The "Request" and "Indication" services contain the same data; the
difference is in the perspective ("Request' from the master's perspective,
"Indication" from the slave's perspective).
If the master sends a service to the slave, the first word is the control
word. If, however, an answer is sent from the slave to the master, the first
word is the status word. Both words control the sequence of the Service
Data Channel.
If the data to be transmitted are longer than the length of the Service Data
Channel, they must be fragmented. The required information is also
contained in the control/status word. The total length that may be
transmitted via the Service Data Channel is 128 bytes.
Command Communications
(Readout of the requested data)
(Readout of the response telegram)
(Read request)
(Write request)
Read
Response
Read
Confirmation
Fieldbus
Write
Response
Write
Confirmation
Fieldbus
11-11
Slave
Read
Indication
Slave
Write
Indication
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